platform_bionic/libc/private/bionic_allocator.h
Vy Nguyen d500751443 Add a thread-properties API
(Based on proposal at https://sourceware.org/glibc/wiki/ThreadPropertiesAPI)

This includes API to:
 - locate static and dynamic TLS
 - register thread-exit and  dynamic TLS creation/destruction callbacks

Change-Id: Icd9d29a5b2f47495395645e19d3b2c96826f19c8
2020-08-11 16:51:43 +00:00

128 lines
4.4 KiB
C++

/*
* Copyright (C) 2015 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include <errno.h>
#include <stdlib.h>
#include <sys/cdefs.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <stddef.h>
#include <unistd.h>
const uint32_t kSmallObjectMaxSizeLog2 = 10;
const uint32_t kSmallObjectMinSizeLog2 = 4;
const uint32_t kSmallObjectAllocatorsCount = kSmallObjectMaxSizeLog2 - kSmallObjectMinSizeLog2 + 1;
class BionicSmallObjectAllocator;
// This structure is placed at the beginning of each addressable page
// and has all information we need to find the corresponding memory allocator.
struct page_info {
char signature[4];
uint32_t type;
union {
// we use allocated_size for large objects allocator
size_t allocated_size;
// and allocator_addr for small ones.
BionicSmallObjectAllocator* allocator_addr;
};
};
struct small_object_block_record {
small_object_block_record* next;
size_t free_blocks_cnt;
};
// This structure is placed at the beginning of each page managed by
// BionicSmallObjectAllocator. Note that a page_info struct is expected at the
// beginning of each page as well, and therefore this structure contains a
// page_info as its *first* field.
struct small_object_page_info {
page_info info; // Must be the first field.
// Doubly linked list for traversing all pages allocated by a
// BionicSmallObjectAllocator.
small_object_page_info* next_page;
small_object_page_info* prev_page;
// Linked list containing all free blocks in this page.
small_object_block_record* free_block_list;
// Free blocks counter.
size_t free_blocks_cnt;
};
class BionicSmallObjectAllocator {
public:
BionicSmallObjectAllocator(uint32_t type, size_t block_size);
void* alloc();
void free(void* ptr);
size_t get_block_size() const { return block_size_; }
private:
void alloc_page();
void free_page(small_object_page_info* page);
void add_to_page_list(small_object_page_info* page);
void remove_from_page_list(small_object_page_info* page);
const uint32_t type_;
const size_t block_size_;
const size_t blocks_per_page_;
size_t free_pages_cnt_;
small_object_page_info* page_list_;
};
class BionicAllocator {
public:
constexpr BionicAllocator() : allocators_(nullptr), allocators_buf_() {}
void* alloc(size_t size);
void* memalign(size_t align, size_t size);
// Note that this implementation of realloc never shrinks allocation
void* realloc(void* ptr, size_t size);
void free(void* ptr);
// Returns the size of the given allocated heap chunk, if it is valid.
// Otherwise, this may return 0 or cause a segfault if the pointer is invalid.
size_t get_chunk_size(void* ptr);
private:
void* alloc_mmap(size_t align, size_t size);
inline void* alloc_impl(size_t align, size_t size);
inline page_info* get_page_info_unchecked(void* ptr);
inline page_info* get_page_info(void* ptr);
BionicSmallObjectAllocator* get_small_object_allocator(uint32_t type);
void initialize_allocators();
BionicSmallObjectAllocator* allocators_;
uint8_t allocators_buf_[sizeof(BionicSmallObjectAllocator)*kSmallObjectAllocatorsCount];
};